The present invention claims priority from Japanese Patent Application No. 11-125231 filed Apr. 30, 1999, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an asynchronous transfer mode (referred to as ATM, hereinafter) switch used in an ATM network system and, particularly, to an ATM switch for use in a wireless ATM (referred to as WATM, hereinafter) network system with which the mobility of terminal station is realized.
2. Description of the Related Art
As the technique for supporting a mobility of a terminal station in a WATM network system, (SIG+M), which is the existing signaling function (referred to as SIG, hereinafter) added with a mobility support function (referred to as M, hereinafter) of the terminal station, was discussed in xe2x80x9cWireless ATM Capability Set1 Specification-Draft BTD-WATM-01.10xe2x80x9d; Dec. 19, 1998, Nashville, USA, ATM Forum. That is, in order to realize the WATM network system, it is necessary to construct an architecture of the end user mobility supporting ATM switch (referred to as EMAS, hereinafter) in which the signaling function (SIG+M) is applied to an SIG protocol of the existing ATM switch.
In a case where a usual ATM switch having no mobility supporting unction of a terminal station is connected to the EMAS, however, a signaling ignal (SIG signal) is terminated by the ATM switch. Therefore, a signaling ignal (SIG+M signal) having the terminal station mobility supporting function is also terminated by the ATM switch. That is, when both an EMAS and a usual ATM switch, which are multi-stage connected, exist in a WATM network, the SIG+M signal is terminated by the usual ATM switch. Therefore, it has been impossible to construct the WATM network in the network system including usual ATM switch.
An object of the present invention is to provide an ATM switch in concord with a WATM network by providing a location manager or a location server having a mobility supporting function of a terminal station on a usual ATM switch having no mobility supporting function of the terminal station and a control method of the same ATM switch.
In order to achieve the above object of the present invention, an ATM switch used to perform a switching of ATM cells on an ATM network system in transferring the ATM cells is featured by comprising switching control means for controlling routes for switching means for executing a switching of the ATM cells required to take all input data in and routes of ports from which the input data is output, access point control protocol (APCP) processing means for translating a content of a signaling processing in a call control means into a message according to an APCP, which is a communication protocol for performing a communication with an access point, SIG+M processing means for performing a signaling termination and for executing the APCP message by translating the APCP message into the SIG+M signal, which is a signaling signal added with a mobility supporting function of a terminal station, ATM cell header conversion means for converting an ATM cell header of the SIG+M signal into virtual path identifier/virtual channel identifier (VPI/VCI) used in a user cell, inserting an identifier indicating that the converted cell is the SIG+M into a payload and transferring it to the SIG+M processing means, the ATM cell header conversion means being adapted to restore the SIG+M message and transfer it to the SIG+M processing means when a cell of the SIG+M signal converted into the VPI/VCI of the user cell header is received, the SIG+M processing means being adapted to match, as an interface with respect to the call control means, the call control means with the SIG+M processing mean, a call control interface means for recognizing a special signaling message used in the mobility supporting function of a terminal station, performing a termination processing for the special signaling message and exchanging signals with the APCP processing means. The SIG+M processing means includes movement manager for managing a movement of a terminal station, security manager for performing required security control and service control means for performing required service control.
The switching control means, the APCP processing means, the SIG+M means and the ATM cell header conversion means are provided on the network side of the switch means.
The movement manager may include a corresponding table between a location area for performing a routing control during a paging or hand-off and access points stored in the ATM switch.
Further, in order to achieve the above object of the present invention, an ATM switch control method for controlling an ATM switch used in switching in transferring ATM cells on an ATM network system is featured by comprising, in an ATM cell transfer processing requested from a terminal station in an uplink direction, the steps of controlling switch means for switching ATM cells to determine a route for taking all input data and to determine a route of an output port, converting an ATM cell header of a SIG+M signal into a VPI/VCI used in a user cell, performing a required security control and service control by recognizing a special signaling message used in a mobility supporting function of the terminal station by using the SIG+M signal converted into the VPI/VCI, performing a termination processing for the special signaling and managing a movement of the terminal station, performing, on demand, a communication with an access point by translating the signaling message into an APCP message, which is a communication protocol for communication with the access point, and using the translated APCP message, and performing an output route control of the SIG+M processed signaling message and the user cell to the network by the switch means, and, in an ATM cell transfer processing in a down-link to the terminal station, the steps of controlling switch means for switching ATM cells to determine a route for taking all input data and to determine a route of an output port, restoring the SIG+M message of a cell by receiving the cell of the VPI/VCI converted SIG+M signal of the user cell header, performing a required security control and service control by recognizing the special signaling message used in the mobility supporting function of the terminal station by using the restored SIG+M signal, performing a termination processing for the special signaling and managing a movement of the terminal station, performing, on demand, a communication with an access point by translating the signaling message into an APCP message, which is a communication protocol for communication with the access point, and using the translated APCP message, and performing an output route control of the SIG+M processed signaling message and the user cell to the terminal station by the switch means.
In the case of the up-link ATM cell transfer processing requested by the terminal station, the step of converting the ATM cell header of the SIG+M signal into the VPI/VCI includes the step of inserting an identifier indicating that the converted cell is the SIG+M is inserted into a payload and, in the case of the down-link ATM transfer processing to the terminal station, the step of restoring the SIM+M message of a cell by receiving the cell of the SIG+M signal includes the steps of filtering the received ATM cell and restoring the SIM+M message on a basis of the identifier when the identifier inserted into a portion of the payload is detected.
Further, in order to achieve the above object of the present invention, a memory medium storing a switching control program for controlling an ATM switch used in the switching in transferring an ATM cell on an ATM network is featured by storing, in an ATM cell transfer processing requested from a terminal station in an up-link direction, the steps of controlling switch means for switching ATM cells to determine a route for taking all input data and to determine a route of an output port, converting an ATM cell header of a SIG+M signal into a VPI/VCI used in a user cell, performing a required security control and service control by recognizing a special signaling message used in a mobility supporting function of the terminal station by using the SIG+M signal converted into the VPI/VCI, performing a termination processing for the special signaling and managing a movement of the terminal station, performing, on demand, a communication with an access point by translating the signaling message into an APCP message, which is a communication protocol for communication with the access point, and using the translated APCP message, and performing an output routing control of the SIG+M processed signaling message and the user cell to the network by the switch means, and, in an ATM cell transfer processing in a down-link to the terminal station, the steps of controlling switch means for switching ATM cells to determine a route for taking all input data and to determine a routing of an output port, restoring the SIG+M message of a cell by receiving the cell of the VPI/VCI converted SIG+M signal of the user cell header, performing a required security control and service control by recognizing the special signaling message used in the mobility supporting function of the terminal station by using the restored SIG+M signal, performing a termination processing for the special signaling and managing a movement of the terminal station, performing, on demand, a communication with an access point by translating the signaling message into an APCP message, which is a communication protocol for communication with the access point, and using the translated APCP message, and performing an output route control of the SIG+M processed signaling message and the user cell to the terminal station by the switch means.